PCP: support for 'dynamic columns' added at runtime

Implements support for arbitrary Performance Co-Pilot
metrics with per-process instance domains to form new
htop columns.  The column-to-metric mappings are setup
using configuration files which will be documented via
man pages as part of a follow-up commit.

We provide an initial set of column configurations so
as to provide new capabilities to pcp-htop: including
configs for containers, open fd counts, scheduler run
queue time, tcp/udp bytes/calls sent/recv, delay acct,
virtual machine guests, detailed virtual memory, swap.

Note there is a change to the configuration file path
resolution algorithm introduced for 'dynamic meters'.
First, look in any custom PCP_HTOP_DIR location.  Then
iterate, in priority order, users home directory, then
local sysadmins files in /etc/pcp/htop, then readonly
configuration files below /usr/share/pcp/htop.  This
final location becomes the preferred place for our own
shipped meter and column files.

The Settings file (htoprc) writing code is updated to
not using the numeric identifier for dynamic columns.
The same strategy used for dynamic meters is used here
where we write Dynamic(name) so the name can be setup
once more at start.  Regular (static) columns writing
to htoprc - i.e. numerically indexed - is unchanged.

20 files changed, 692 insertions, 77 deletions

diff --git a/pcp/PCPDynamicColumn.c b/pcp/PCPDynamicColumn.c
new file mode 100644
index 00000000..2848490e
--- /dev/null
+++ b/pcp/PCPDynamicColumn.c
@@ -0,0 +1,326 @@
+/*
+htop - PCPDynamicColumn.c
+(C) 2021 Sohaib Mohammed
+(C) 2021 htop dev team
+(C) 2021 Red Hat, Inc.
+Released under the GNU GPLv2, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include "config.h" // IWYU pragma: keep
+
+#include "pcp/PCPDynamicColumn.h"
+
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "CRT.h"
+#include "Macros.h"
+#include "Platform.h"
+#include "Process.h"
+#include "RichString.h"
+#include "XUtils.h"
+
+#include "pcp/PCPProcess.h"
+
+
+static bool PCPDynamicColumn_addMetric(PCPDynamicColumns* columns, PCPDynamicColumn* column) {
+   if (!column->super.name[0])
+      return false;
+
+   size_t bytes = 16 + strlen(column->super.name);
+   char* metricName = xMalloc(bytes);
+   xSnprintf(metricName, bytes, "htop.column.%s", column->super.name);
+
+   column->metricName = metricName;
+   column->id = columns->offset + columns->cursor;
+   columns->cursor++;
+
+   Platform_addMetric(column->id, metricName);
+   return true;
+}
+
+static void PCPDynamicColumn_parseMetric(PCPDynamicColumns* columns, PCPDynamicColumn* column, const char* path, unsigned int line, char* value) {
+   /* lookup a dynamic metric with this name, else create */
+   if (PCPDynamicColumn_addMetric(columns, column) == false)
+      return;
+
+   /* derived metrics in all dynamic columns for simplicity */
+   char* error;
+   if (pmRegisterDerivedMetric(column->metricName, value, &error) < 0) {
+      char* note;
+      xAsprintf(&note,
+                "%s: failed to parse expression in %s at line %u\n%s\n",
+                pmGetProgname(), path, line, error);
+      free(error);
+      errno = EINVAL;
+      CRT_fatalError(note);
+      free(note);
+   }
+}
+
+// Ensure a valid name for use in a PCP metric name and in htoprc
+static bool PCPDynamicColumn_validateColumnName(char* key, const char* path, unsigned int line) {
+   char* p = key;
+   char* end = strrchr(key, ']');
+
+   if (end) {
+      *end = '\0';
+   } else {
+      fprintf(stderr,
+                "%s: no closing brace on column name at %s line %u\n\"%s\"",
+                pmGetProgname(), path, line, key);
+      return false;
+   }
+
+   while (*p) {
+      if (p == key) {
+         if (!isalpha(*p) && *p != '_')
+            break;
+      } else {
+         if (!isalnum(*p) && *p != '_')
+            break;
+      }
+      p++;
+   }
+   if (*p != '\0') { /* badness */
+      fprintf(stderr,
+                "%s: invalid column name at %s line %u\n\"%s\"",
+                pmGetProgname(), path, line, key);
+      return false;
+   }
+   return true;
+}
+
+// Ensure a column name has not been defined previously
+static bool PCPDynamicColumn_uniqueName(char* key, PCPDynamicColumns* columns) {
+   return DynamicColumn_search(columns->table, key, NULL) == NULL;
+}
+
+static PCPDynamicColumn* PCPDynamicColumn_new(PCPDynamicColumns* columns, const char* name) {
+   PCPDynamicColumn* column = xCalloc(1, sizeof(*column));
+   String_safeStrncpy(column->super.name, name, sizeof(column->super.name));
+
+   size_t id = columns->count + LAST_PROCESSFIELD;
+   Hashtable_put(columns->table, id, column);
+   columns->count++;
+
+   return column;
+}
+
+static void PCPDynamicColumn_parseFile(PCPDynamicColumns* columns, const char* path) {
+   FILE* file = fopen(path, "r");
+   if (!file)
+      return;
+
+   PCPDynamicColumn* column = NULL;
+   unsigned int lineno = 0;
+   bool ok = true;
+   for (;;) {
+      char* line = String_readLine(file);
+      if (!line)
+         break;
+      lineno++;
+
+      /* cleanup whitespace, skip comment lines */
+      char* trimmed = String_trim(line);
+      free(line);
+      if (!trimmed || !trimmed[0] || trimmed[0] == '#') {
+         free(trimmed);
+         continue;
+      }
+
+      size_t n;
+      char** config = String_split(trimmed, '=', &n);
+      free(trimmed);
+      if (config == NULL)
+         continue;
+
+      char* key = String_trim(config[0]);
+      char* value = n > 1 ? String_trim(config[1]) : NULL;
+      if (key[0] == '[') {  /* new section heading - i.e. new column */
+         ok = PCPDynamicColumn_validateColumnName(key + 1, path, lineno);
+         if (ok)
+            ok = PCPDynamicColumn_uniqueName(key + 1, columns);
+         if (ok)
+            column = PCPDynamicColumn_new(columns, key + 1);
+      } else if (value && column && String_eq(key, "caption")) {
+         free_and_xStrdup(&column->super.caption, value);
+      } else if (value && column && String_eq(key, "heading")) {
+         free_and_xStrdup(&column->super.heading, value);
+      } else if (value && column && String_eq(key, "description")) {
+         free_and_xStrdup(&column->super.description, value);
+      } else if (value && column && String_eq(key, "width")) {
+         column->super.width = strtoul(value, NULL, 10);
+      } else if (value && column && String_eq(key, "metric")) {
+         PCPDynamicColumn_parseMetric(columns, column, path, lineno, value);
+      }
+      String_freeArray(config);
+      free(value);
+      free(key);
+   }
+   fclose(file);
+}
+
+static void PCPDynamicColumn_scanDir(PCPDynamicColumns* columns, char* path) {
+   DIR* dir = opendir(path);
+   if (!dir)
+      return;
+
+   struct dirent* dirent;
+   while ((dirent = readdir(dir)) != NULL) {
+      if (dirent->d_name[0] == '.')
+         continue;
+
+      char* file = String_cat(path, dirent->d_name);
+      PCPDynamicColumn_parseFile(columns, file);
+      free(file);
+   }
+   closedir(dir);
+}
+
+void PCPDynamicColumns_init(PCPDynamicColumns* columns) {
+   const char* share = pmGetConfig("PCP_SHARE_DIR");
+   const char* sysconf = pmGetConfig("PCP_SYSCONF_DIR");
+   const char* xdgConfigHome = getenv("XDG_CONFIG_HOME");
+   const char* override = getenv("PCP_HTOP_DIR");
+   const char* home = getenv("HOME");
+   char* path;
+
+   columns->table = Hashtable_new(0, true);
+
+   /* developer paths - PCP_HTOP_DIR=./pcp ./pcp-htop */
+   if (override) {
+      path = String_cat(override, "/columns/");
+      PCPDynamicColumn_scanDir(columns, path);
+      free(path);
+   }
+
+   /* next, search in home directory alongside htoprc */
+   if (xdgConfigHome)
+      path = String_cat(xdgConfigHome, "/htop/columns/");
+   else if (home)
+      path = String_cat(home, "/.config/htop/columns/");
+   else
+      path = NULL;
+   if (path) {
+      PCPDynamicColumn_scanDir(columns, path);
+      free(path);
+   }
+
+   /* next, search in the system columns directory */
+   path = String_cat(sysconf, "/htop/columns/");
+   PCPDynamicColumn_scanDir(columns, path);
+   free(path);
+
+   /* next, try the readonly system columns directory */
+   path = String_cat(share, "/htop/columns/");
+   PCPDynamicColumn_scanDir(columns, path);
+   free(path);
+}
+
+void PCPDynamicColumn_writeField(PCPDynamicColumn* this, const Process* proc, RichString* str) {
+   const PCPProcess* pp = (const PCPProcess*) proc;
+   unsigned int type = Metric_type(this->id);
+
+   pmAtomValue atom;
+   if (!Metric_instance(this->id, proc->pid, pp->offset, &atom, type)) {
+      RichString_appendAscii(str, CRT_colors[METER_VALUE_ERROR], "no data");
+      return;
+   }
+
+   int width = this->super.width;
+   if (!width || abs(width) > DYNAMIC_MAX_COLUMN_WIDTH)
+      width = DYNAMIC_DEFAULT_COLUMN_WIDTH;
+   int abswidth = abs(width);
+   if (abswidth > DYNAMIC_MAX_COLUMN_WIDTH) {
+      abswidth = DYNAMIC_MAX_COLUMN_WIDTH;
+      width = -abswidth;
+   }
+
+   char buffer[DYNAMIC_MAX_COLUMN_WIDTH + /* space */ 1 + /* null terminator */ + 1];
+   int attr = CRT_colors[DEFAULT_COLOR];
+   switch (type) {
+      case PM_TYPE_STRING:
+         attr = CRT_colors[PROCESS_SHADOW];
+         Process_printLeftAlignedField(str, attr, atom.cp, abswidth);
+         free(atom.cp);
+         break;
+      case PM_TYPE_32:
+         xSnprintf(buffer, sizeof(buffer), "%*d ", width, atom.l);
+         RichString_appendAscii(str, attr, buffer);
+         break;
+      case PM_TYPE_U32:
+         xSnprintf(buffer, sizeof(buffer), "%*u ", width, atom.ul);
+         RichString_appendAscii(str, attr, buffer);
+         break;
+      case PM_TYPE_64:
+         xSnprintf(buffer, sizeof(buffer), "%*lld ", width, (long long) atom.ll);
+         RichString_appendAscii(str, attr, buffer);
+         break;
+      case PM_TYPE_U64:
+         xSnprintf(buffer, sizeof(buffer), "%*llu ", width, (unsigned long long) atom.ull);
+         RichString_appendAscii(str, attr, buffer);
+         break;
+      case PM_TYPE_FLOAT:
+         xSnprintf(buffer, sizeof(buffer), "%*.2f ", width, (double) atom.f);
+         RichString_appendAscii(str, attr, buffer);
+         break;
+      case PM_TYPE_DOUBLE:
+         xSnprintf(buffer, sizeof(buffer), "%*.2f ", width, atom.d);
+         RichString_appendAscii(str, attr, buffer);
+         break;
+      default:
+         attr = CRT_colors[METER_VALUE_ERROR];
+         RichString_appendAscii(str, attr, "no type");
+         break;
+   }
+}
+
+int PCPDynamicColumn_compareByKey(const PCPProcess* p1, const PCPProcess* p2, ProcessField key) {
+   const PCPDynamicColumn* column = Hashtable_get(p1->super.processList->dynamicColumns, key);
+
+   size_t metric = column->id;
+   unsigned int type = Metric_type(metric);
+
+   pmAtomValue atom1 = {0}, atom2 = {0};
+   if (!Metric_instance(metric, p1->super.pid, p1->offset, &atom1, type) ||
+       !Metric_instance(metric, p2->super.pid, p2->offset, &atom2, type)) {
+      if (type == PM_TYPE_STRING) {
+         free(atom1.cp);
+         free(atom2.cp);
+      }
+      return -1;
+   }
+
+   switch (type) {
+      case PM_TYPE_STRING: {
+         int cmp = SPACESHIP_NULLSTR(atom2.cp, atom1.cp);
+         free(atom2.cp);
+         free(atom1.cp);
+         return cmp;
+      }
+      case PM_TYPE_32:
+         return SPACESHIP_NUMBER(atom2.l, atom1.l);
+      case PM_TYPE_U32:
+         return SPACESHIP_NUMBER(atom2.ul, atom1.ul);
+      case PM_TYPE_64:
+         return SPACESHIP_NUMBER(atom2.ll, atom1.ll);
+      case PM_TYPE_U64:
+         return SPACESHIP_NUMBER(atom2.ull, atom1.ull);
+      case PM_TYPE_FLOAT:
+         return SPACESHIP_NUMBER(atom2.f, atom1.f);
+      case PM_TYPE_DOUBLE:
+         return SPACESHIP_NUMBER(atom2.d, atom1.d);
+      default:
+         break;
+   }
+   return -1;
+}
diff --git a/pcp/PCPDynamicColumn.h b/pcp/PCPDynamicColumn.h
new file mode 100644
index 00000000..39f79358
--- /dev/null
+++ b/pcp/PCPDynamicColumn.h
@@ -0,0 +1,32 @@
+#ifndef HEADER_PCPDynamicColumn
+#define HEADER_PCPDynamicColumn
+
+#include "CRT.h"
+#include "DynamicColumn.h"
+#include "Hashtable.h"
+#include "Process.h"
+#include "RichString.h"
+
+#include "pcp/PCPProcess.h"
+
+
+typedef struct PCPDynamicColumn_ {
+   DynamicColumn super;
+   char* metricName;
+   size_t id;  /* identifier for metric array lookups */
+} PCPDynamicColumn;
+
+typedef struct PCPDynamicColumns_ {
+   Hashtable* table;
+   size_t count;  /* count of dynamic meters discovered by scan */
+   size_t offset; /* start offset into the Platform metric array */
+   size_t cursor; /* identifier allocator for each new metric used */
+} PCPDynamicColumns;
+
+void PCPDynamicColumns_init(PCPDynamicColumns* columns);
+
+void PCPDynamicColumn_writeField(PCPDynamicColumn* this, const Process* proc, RichString* str);
+
+int PCPDynamicColumn_compareByKey(const PCPProcess* p1, const PCPProcess* p2, ProcessField key);
+
+#endif
diff --git a/pcp/PCPDynamicMeter.c b/pcp/PCPDynamicMeter.c
index ffde2b4f..b90511ec 100644
--- a/pcp/PCPDynamicMeter.c
+++ b/pcp/PCPDynamicMeter.c
@@ -1,7 +1,7 @@
 /*
 htop - PCPDynamicMeter.c
 (C) 2021 htop dev team
-(C) 2021 Red Hat, Inc.  All Rights Reserved.
+(C) 2021 Red Hat, Inc.
 Released under the GNU GPLv2, see the COPYING file
 in the source distribution for its full text.
 */
@@ -18,13 +18,14 @@ in the source distribution for its full text.
 #include "Settings.h"
 #include "XUtils.h"
 
+
 static PCPDynamicMetric* PCPDynamicMeter_lookupMetric(PCPDynamicMeters* meters, PCPDynamicMeter* meter, const char* name) {
-   size_t bytes = 8 + strlen(meter->super.name) + strlen(name);
+   size_t bytes = 16 + strlen(meter->super.name) + strlen(name);
    char* metricName = xMalloc(bytes);
-   xSnprintf(metricName, bytes, "htop.%s.%s", meter->super.name, name);
+   xSnprintf(metricName, bytes, "htop.meter.%s.%s", meter->super.name, name);
 
    PCPDynamicMetric* metric;
-   for (unsigned int i = 0; i < meter->totalMetrics; i++) {
+   for (size_t i = 0; i < meter->totalMetrics; i++) {
       metric = &meter->metrics[i];
       if (String_eq(metric->name, metricName)) {
          free(metricName);
@@ -33,7 +34,7 @@ static PCPDynamicMetric* PCPDynamicMeter_lookupMetric(PCPDynamicMeters* meters,
    }
 
    /* not an existing metric in this meter - add it */
-   unsigned int n = meter->totalMetrics + 1;
+   size_t n = meter->totalMetrics + 1;
    meter->metrics = xReallocArray(meter->metrics, n, sizeof(PCPDynamicMetric));
    meter->totalMetrics = n;
    metric = &meter->metrics[n - 1];
@@ -139,13 +140,8 @@ static bool PCPDynamicMeter_validateMeterName(char* key, const char* path, unsig
 }
 
 // Ensure a meter name has not been defined previously
-static bool PCPDynamicMeter_uniqueName(char* key, const char* path, unsigned int line, PCPDynamicMeters* meters) {
-   if (DynamicMeter_search(meters->table, key, NULL) == false)
-      return true;
-
-   fprintf(stderr, "%s: duplicate name at %s line %u: \"%s\", ignored\n",
-           pmGetProgname(), path, line, key);
-   return false;
+static bool PCPDynamicMeter_uniqueName(char* key, PCPDynamicMeters* meters) {
+   return !DynamicMeter_search(meters->table, key, NULL);
 }
 
 static PCPDynamicMeter* PCPDynamicMeter_new(PCPDynamicMeters* meters, const char* name) {
@@ -188,7 +184,7 @@ static void PCPDynamicMeter_parseFile(PCPDynamicMeters* meters, const char* path
       if (key[0] == '[') {  /* new section heading - i.e. new meter */
          ok = PCPDynamicMeter_validateMeterName(key + 1, path, lineno);
          if (ok)
-            ok = PCPDynamicMeter_uniqueName(key + 1, path, lineno, meters);
+            ok = PCPDynamicMeter_uniqueName(key + 1, meters);
          if (ok)
             meter = PCPDynamicMeter_new(meters, key + 1);
       } else if (!ok) {
@@ -241,40 +237,47 @@ static void PCPDynamicMeter_scanDir(PCPDynamicMeters* meters, char* path) {
 }
 
 void PCPDynamicMeters_init(PCPDynamicMeters* meters) {
+   const char* share = pmGetConfig("PCP_SHARE_DIR");
    const char* sysconf = pmGetConfig("PCP_SYSCONF_DIR");
    const char* xdgConfigHome = getenv("XDG_CONFIG_HOME");
+   const char* override = getenv("PCP_HTOP_DIR");
    const char* home = getenv("HOME");
    char* path;
 
    meters->table = Hashtable_new(0, true);
 
-   /* search in the users home directory first of all */
-   if (xdgConfigHome) {
+   /* developer paths - PCP_HTOP_DIR=./pcp ./pcp-htop */
+   if (override) {
+      path = String_cat(override, "/meters/");
+      PCPDynamicMeter_scanDir(meters, path);
+      free(path);
+   }
+
+   /* next, search in home directory alongside htoprc */
+   if (xdgConfigHome)
       path = String_cat(xdgConfigHome, "/htop/meters/");
-   } else {
-      if (!home)
-         home = "";
+   else if (home)
       path = String_cat(home, "/.config/htop/meters/");
+   else
+      path = NULL;
+   if (path) {
+      PCPDynamicMeter_scanDir(meters, path);
+      free(path);
    }
-   PCPDynamicMeter_scanDir(meters, path);
-   free(path);
 
-   /* secondly search in the system meters directory */
+   /* next, search in the system meters directory */
    path = String_cat(sysconf, "/htop/meters/");
    PCPDynamicMeter_scanDir(meters, path);
    free(path);
 
-   /* check the working directory, as a final option */
-   char cwd[PATH_MAX];
-   if (getcwd(cwd, sizeof(cwd)) != NULL) {
-      path = String_cat(cwd, "/pcp/meters/");
-      PCPDynamicMeter_scanDir(meters, path);
-      free(path);
-   }
+   /* next, try the readonly system meters directory */
+   path = String_cat(share, "/htop/meters/");
+   PCPDynamicMeter_scanDir(meters, path);
+   free(path);
 }
 
 void PCPDynamicMeter_enable(PCPDynamicMeter* this) {
-   for (unsigned int i = 0; i < this->totalMetrics; i++)
+   for (size_t i = 0; i < this->totalMetrics; i++)
       Metric_enable(this->metrics[i].id, true);
 }
 
@@ -283,7 +286,7 @@ void PCPDynamicMeter_updateValues(PCPDynamicMeter* this, Meter* meter) {
    size_t size = sizeof(meter->txtBuffer);
    size_t bytes = 0;
 
-   for (unsigned int i = 0; i < this->totalMetrics; i++) {
+   for (size_t i = 0; i < this->totalMetrics; i++) {
       if (i > 0 && bytes < size - 1)
          buffer[bytes++] = '/';  /* separator */
 
@@ -357,7 +360,7 @@ void PCPDynamicMeter_updateValues(PCPDynamicMeter* this, Meter* meter) {
 void PCPDynamicMeter_display(PCPDynamicMeter* this, ATTR_UNUSED const Meter* meter, RichString* out) {
    int nodata = 1;
 
-   for (unsigned int i = 0; i < this->totalMetrics; i++) {
+   for (size_t i = 0; i < this->totalMetrics; i++) {
       PCPDynamicMetric* metric = &this->metrics[i];
       const pmDesc* desc = Metric_desc(metric->id);
       pmAtomValue atom, raw;
diff --git a/pcp/PCPDynamicMeter.h b/pcp/PCPDynamicMeter.h
index a7390e61..cfe488e5 100644
--- a/pcp/PCPDynamicMeter.h
+++ b/pcp/PCPDynamicMeter.h
@@ -4,25 +4,26 @@
 #include "CRT.h"
 #include "DynamicMeter.h"
 
-typedef struct {
-   unsigned int id; /* index into metric array */
+
+typedef struct PCPDynamicMetric_ {
+   size_t id; /* index into metric array */
    ColorElements color;
    char* name; /* derived metric name */
    char* label;
    char* suffix;
 } PCPDynamicMetric;
 
-typedef struct {
+typedef struct PCPDynamicMeter_ {
    DynamicMeter super;
    PCPDynamicMetric* metrics;
-   unsigned int totalMetrics;
+   size_t totalMetrics;
 } PCPDynamicMeter;
 
-typedef struct {
+typedef struct PCPDynamicMeters_ {
    Hashtable* table;
-   unsigned int count; /* count of dynamic meters discovered by scan */
-   unsigned int offset; /* start offset into the Platform metric array */
-   unsigned int cursor; /* identifier allocator for each new metric used */
+   size_t count;  /* count of dynamic meters discovered by scan */
+   size_t offset; /* start offset into the Platform metric array */
+   size_t cursor; /* identifier allocator for each new metric used */
 } PCPDynamicMeters;
 
 void PCPDynamicMeters_init(PCPDynamicMeters* meters);
diff --git a/pcp/PCPProcess.c b/pcp/PCPProcess.c
index 993a746f..93043c04 100644
--- a/pcp/PCPProcess.c
+++ b/pcp/PCPProcess.c
@@ -1,8 +1,8 @@
 /*
 htop - PCPProcess.c
 (C) 2014 Hisham H. Muhammad
-(C) 2020 htop dev team
-(C) 2020-2021 Red Hat, Inc.  All Rights Reserved.
+(C) 2020-2021 htop dev team
+(C) 2020-2021 Red Hat, Inc.
 Released under the GNU GPLv2, see the COPYING file
 in the source distribution for its full text.
 */
@@ -12,15 +12,18 @@ in the source distribution for its full text.
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
-#include <syscall.h>
-#include <unistd.h>
 
 #include "CRT.h"
+#include "Macros.h"
+#include "Platform.h"
 #include "Process.h"
 #include "ProvideCurses.h"
+#include "RichString.h"
 #include "XUtils.h"
 
+#include "pcp/PCPDynamicColumn.h"
+
+
 const ProcessFieldData Process_fields[] = {
    [0] = { .name = "", .title = NULL, .description = NULL, .flags = 0, },
    [PID] = { .name = "PID", .title = "PID", .description = "Process/thread ID", .flags = 0, .pidColumn = true, },
@@ -246,7 +249,9 @@ static int PCPProcess_compareByKey(const Process* v1, const Process* v2, Process
    case SECATTR:
       return SPACESHIP_NULLSTR(p1->secattr, p2->secattr);
    default:
-      return Process_compareByKey_Base(v1, v2, key);
+      if (key < LAST_PROCESSFIELD)
+         return Process_compareByKey_Base(v1, v2, key);
+      return PCPDynamicColumn_compareByKey(p1, p2, key);
    }
 }
 
diff --git a/pcp/PCPProcess.h b/pcp/PCPProcess.h
index 25707f2b..42cbd6b1 100644
--- a/pcp/PCPProcess.h
+++ b/pcp/PCPProcess.h
@@ -12,13 +12,13 @@ in the source distribution for its full text.
 #include "config.h" // IWYU pragma: keep
 
 #include <stdbool.h>
-#include <sys/types.h>
 
 #include "Object.h"
 #include "Process.h"
-#include "RichString.h"
 #include "Settings.h"
 
+#include "pcp/Platform.h"
+
 
 #define PROCESS_FLAG_LINUX_CGROUP   0x0800
 #define PROCESS_FLAG_LINUX_OOM      0x1000
@@ -28,6 +28,10 @@ in the source distribution for its full text.
 
 typedef struct PCPProcess_ {
    Process super;
+
+   /* default result offset to use for searching proc metrics */
+   unsigned int offset;
+
    unsigned long int cminflt;
    unsigned long int cmajflt;
    unsigned long long int utime;
diff --git a/pcp/PCPProcessList.c b/pcp/PCPProcessList.c
index ae974435..78e4c809 100644
--- a/pcp/PCPProcessList.c
+++ b/pcp/PCPProcessList.c
@@ -2,7 +2,7 @@
 htop - PCPProcessList.c
 (C) 2014 Hisham H. Muhammad
 (C) 2020-2021 htop dev team
-(C) 2020-2021 Red Hat, Inc.  All Rights Reserved.
+(C) 2020-2021 Red Hat, Inc.
 Released under the GNU GPLv2, see the COPYING file
 in the source distribution for its full text.
 */
@@ -11,11 +11,15 @@ in the source distribution for its full text.
 
 #include "pcp/PCPProcessList.h"
 
+#include <limits.h>
 #include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
 
-#include "CRT.h"
 #include "Macros.h"
 #include "Object.h"
+#include "Platform.h"
 #include "Process.h"
 #include "Settings.h"
 #include "XUtils.h"
@@ -62,11 +66,11 @@ static char* setUser(UsersTable* this, unsigned int uid, int pid, int offset) {
    return name;
 }
 
-ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* dynamicMeters, Hashtable* pidMatchList, uid_t userId) {
+ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* dynamicMeters, Hashtable* dynamicColumns, Hashtable* pidMatchList, uid_t userId) {
    PCPProcessList* this = xCalloc(1, sizeof(PCPProcessList));
    ProcessList* super = &(this->super);
 
-   ProcessList_init(super, Class(PCPProcess), usersTable, dynamicMeters, pidMatchList, userId);
+   ProcessList_init(super, Class(PCPProcess), usersTable, dynamicMeters, dynamicColumns, pidMatchList, userId);
 
    struct timeval timestamp;
    gettimeofday(&timestamp, NULL);
@@ -327,6 +331,7 @@ static bool PCPProcessList_updateProcesses(PCPProcessList* this, double period,
       PCPProcess* pp = (PCPProcess*) proc;
       PCPProcessList_updateID(proc, pid, offset);
       proc->isUserlandThread = proc->pid != proc->tgid;
+      pp->offset = offset >= 0 ? offset : 0;
 
       /*
        * These conditions will not trigger on first occurrence, cause we need to
diff --git a/pcp/PCPProcessList.h b/pcp/PCPProcessList.h
index 7f0f6fe4..07f6c399 100644
--- a/pcp/PCPProcessList.h
+++ b/pcp/PCPProcessList.h
@@ -56,14 +56,14 @@ typedef enum CPUMetric_ {
 
 typedef struct PCPProcessList_ {
    ProcessList super;
-   double timestamp;		/* previous sample timestamp */
-   pmAtomValue* cpu;		/* aggregate values for each metric */
-   pmAtomValue** percpu;	/* per-processor values for each metric */
-   pmAtomValue* values;		/* per-processor buffer for just one metric */
+   double timestamp;     /* previous sample timestamp */
+   pmAtomValue* cpu;     /* aggregate values for each metric */
+   pmAtomValue** percpu; /* per-processor values for each metric */
+   pmAtomValue* values;  /* per-processor buffer for just one metric */
    ZfsArcStats zfs;
 } PCPProcessList;
 
-ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* dynamicMeters, Hashtable* pidMatchList, uid_t userId);
+ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* dynamicMeters, Hashtable* dynamicColumns, Hashtable* pidMatchList, uid_t userId);
 
 void ProcessList_delete(ProcessList* pl);
 
diff --git a/pcp/Platform.c b/pcp/Platform.c
index 4ddf7e68..2854d9bd 100644
--- a/pcp/Platform.c
+++ b/pcp/Platform.c
@@ -2,7 +2,7 @@
 htop - linux/Platform.c
 (C) 2014 Hisham H. Muhammad
 (C) 2020-2021 htop dev team
-(C) 2020-2021 Red Hat, Inc.  All Rights Reserved.
+(C) 2020-2021 Red Hat, Inc.
 Released under the GNU GPLv2, see the COPYING file
 in the source distribution for its full text.
 */
@@ -42,6 +42,7 @@ in the source distribution for its full text.
 #include "linux/PressureStallMeter.h"
 #include "linux/ZramMeter.h"
 #include "linux/ZramStats.h"
+#include "pcp/PCPDynamicColumn.h"
 #include "pcp/PCPDynamicMeter.h"
 #include "pcp/PCPProcess.h"
 #include "pcp/PCPProcessList.h"
@@ -51,19 +52,20 @@ in the source distribution for its full text.
 
 
 typedef struct Platform_ {
-   int context;			/* PMAPI(3) context identifier */
-   unsigned int totalMetrics;	/* total number of all metrics */
-   const char** names;		/* name array indexed by Metric */
-   pmID* pmids;			/* all known metric identifiers */
-   pmID* fetch;			/* enabled identifiers for sampling */
-   pmDesc* descs;		/* metric desc array indexed by Metric */
-   pmResult* result;		/* sample values result indexed by Metric */
-   PCPDynamicMeters meters;	/* dynamic meters via configuration files */
-   struct timeval offset;	/* time offset used in archive mode only */
-   long long btime;		/* boottime in seconds since the epoch */
-   char* release;		/* uname and distro from this context */
-   int pidmax;			/* maximum platform process identifier */
-   int ncpu;			/* maximum processor count configured */
+   int context;               /* PMAPI(3) context identifier */
+   size_t totalMetrics;       /* total number of all metrics */
+   const char** names;        /* name array indexed by Metric */
+   pmID* pmids;               /* all known metric identifiers */
+   pmID* fetch;               /* enabled identifiers for sampling */
+   pmDesc* descs;             /* metric desc array indexed by Metric */
+   pmResult* result;          /* sample values result indexed by Metric */
+   PCPDynamicMeters meters;   /* dynamic meters via configuration files */
+   PCPDynamicColumns columns; /* dynamic columns via configuration files */
+   struct timeval offset;     /* time offset used in archive mode only */
+   long long btime;           /* boottime in seconds since the epoch */
+   char* release;             /* uname and distro from this context */
+   int pidmax;                /* maximum platform process identifier */
+   int ncpu;                  /* maximum processor count configured */
 } Platform;
 
 Platform* pcp;
@@ -251,6 +253,10 @@ const pmDesc* Metric_desc(Metric metric) {
    return &pcp->descs[metric];
 }
 
+int Metric_type(Metric metric) {
+   return pcp->descs[metric].type;
+}
+
 pmAtomValue* Metric_values(Metric metric, pmAtomValue* atom, int count, int type) {
    if (pcp->result == NULL)
       return NULL;
@@ -398,12 +404,12 @@ bool Metric_fetch(struct timeval* timestamp) {
    return true;
 }
 
-int Platform_addMetric(Metric id, const char* name) {
+size_t Platform_addMetric(Metric id, const char* name) {
    unsigned int i = (unsigned int)id;
 
    if (i >= PCP_METRIC_COUNT && i >= pcp->totalMetrics) {
       /* added via configuration files */
-      unsigned int j = pcp->totalMetrics + 1;
+      size_t j = pcp->totalMetrics + 1;
       pcp->fetch = xRealloc(pcp->fetch, j * sizeof(pmID));
       pcp->pmids = xRealloc(pcp->pmids, j * sizeof(pmID));
       pcp->names = xRealloc(pcp->names, j * sizeof(char*));
@@ -465,14 +471,17 @@ void Platform_init(void) {
 
    PCPDynamicMeters_init(&pcp->meters);
 
+   pcp->columns.offset = PCP_METRIC_COUNT + pcp->meters.cursor;
+   PCPDynamicColumns_init(&pcp->columns);
+
    sts = pmLookupName(pcp->totalMetrics, pcp->names, pcp->pmids);
    if (sts < 0) {
       fprintf(stderr, "Error: cannot lookup metric names: %s\n", pmErrStr(sts));
       exit(1);
    }
 
-   for (unsigned int i = 0; i < pcp->totalMetrics; i++) {
-      pcp->fetch[i] = PM_ID_NULL;	/* default is to not sample */
+   for (size_t i = 0; i < pcp->totalMetrics; i++) {
+      pcp->fetch[i] = PM_ID_NULL; /* default is to not sample */
 
       /* expect some metrics to be missing - e.g. PMDA not available */
       if (pcp->pmids[i] == PM_ID_NULL)
@@ -501,11 +510,14 @@ void Platform_init(void) {
    Metric_enable(PCP_UNAME_MACHINE, true);
    Metric_enable(PCP_UNAME_DISTRO, true);
 
+   for (size_t i = pcp->columns.offset; i < pcp->columns.offset + pcp->columns.count; i++)
+      Metric_enable(i, true);
+
    Metric_fetch(NULL);
 
    for (Metric metric = 0; metric < PCP_PROC_PID; metric++)
       Metric_enable(metric, true);
-   Metric_enable(PCP_PID_MAX, false);	/* needed one time only */
+   Metric_enable(PCP_PID_MAX, false); /* needed one time only */
    Metric_enable(PCP_BOOTTIME, false);
    Metric_enable(PCP_UNAME_SYSNAME, false);
    Metric_enable(PCP_UNAME_RELEASE, false);
@@ -627,7 +639,7 @@ static double Platform_setOneCPUValues(Meter* this, pmAtomValue* values) {
 
 double Platform_setCPUValues(Meter* this, int cpu) {
    const PCPProcessList* pl = (const PCPProcessList*) this->pl;
-   if (cpu <= 0)	/* use aggregate values */
+   if (cpu <= 0) /* use aggregate values */
       return Platform_setOneCPUValues(this, pl->cpu);
    return Platform_setOneCPUValues(this, pl->percpu[cpu - 1]);
 }
@@ -924,3 +936,29 @@ void Platform_dynamicMeterDisplay(const Meter* meter, RichString* out) {
    if (this)
       PCPDynamicMeter_display(this, meter, out);
 }
+
+Hashtable* Platform_dynamicColumns(void) {
+   return pcp->columns.table;
+}
+
+const char* Platform_dynamicColumnInit(unsigned int key) {
+   PCPDynamicColumn* this = Hashtable_get(pcp->columns.table, key);
+   if (this) {
+      Metric_enable(this->id, true);
+      if (this->super.caption)
+         return this->super.caption;
+      if (this->super.heading)
+         return this->super.heading;
+      return this->super.name;
+   }
+   return NULL;
+}
+
+bool Platform_dynamicColumnWriteField(const Process* proc, RichString* str, unsigned int key) {
+   PCPDynamicColumn* this = Hashtable_get(pcp->columns.table, key);
+   if (this) {
+      PCPDynamicColumn_writeField(this, proc, str);
+      return true;
+   }
+   return false;
+}
diff --git a/pcp/Platform.h b/pcp/Platform.h
index 6b0215c8..76594b9b 100644
--- a/pcp/Platform.h
+++ b/pcp/Platform.h
@@ -11,6 +11,8 @@ in the source distribution for its full text.
 
 #include <ctype.h>
 #include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
 #include <pcp/pmapi.h>
 
 /* use htop config.h values for these macros, not pcp values */
@@ -29,6 +31,7 @@ in the source distribution for its full text.
 #include "NetworkIOMeter.h"
 #include "Process.h"
 #include "ProcessLocksScreen.h"
+#include "RichString.h"
 #include "SignalsPanel.h"
 #include "SysArchMeter.h"
 
@@ -250,13 +253,15 @@ pmAtomValue* Metric_values(Metric metric, pmAtomValue* atom, int count, int type
 
 const pmDesc* Metric_desc(Metric metric);
 
+int Metric_type(Metric metric);
+
 int Metric_instanceCount(Metric metric);
 
 int Metric_instanceOffset(Metric metric, int inst);
 
 pmAtomValue* Metric_instance(Metric metric, int inst, int offset, pmAtomValue* atom, int type);
 
-int Platform_addMetric(Metric id, const char* name);
+size_t Platform_addMetric(Metric id, const char* name);
 
 void Platform_gettime_realtime(struct timeval* tv, uint64_t* msec);
 
@@ -270,4 +275,10 @@ void Platform_dynamicMeterUpdateValues(Meter* meter);
 
 void Platform_dynamicMeterDisplay(const Meter* meter, RichString* out);
 
+Hashtable* Platform_dynamicColumns(void);
+
+const char* Platform_dynamicColumnInit(unsigned int key);
+
+bool Platform_dynamicColumnWriteField(const Process* proc, RichString* str, unsigned int key);
+
 #endif
diff --git a/pcp/columns/container b/pcp/columns/container
new file mode 100644
index 00000000..519288f4
--- /dev/null
+++ b/pcp/columns/container
@@ -0,0 +1,10 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[container]
+heading = Container
+caption = CONTAINER
+width = -12
+metric = proc.id.container
+description = Name of processes container via cgroup heuristics
diff --git a/pcp/columns/delayacct b/pcp/columns/delayacct
new file mode 100644
index 00000000..016904c6
--- /dev/null
+++ b/pcp/columns/delayacct
@@ -0,0 +1,10 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[blkio]
+heading = BLKIOD
+caption = BLKIO_TIME
+width = 6
+metric = proc.psinfo.delayacct_blkio_time
+description = Aggregated block I/O delays
diff --git a/pcp/columns/fdcount b/pcp/columns/fdcount
new file mode 100644
index 00000000..e6794803
--- /dev/null
+++ b/pcp/columns/fdcount
@@ -0,0 +1,10 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[fds]
+heading = FDS
+caption = FDCOUNT
+width = 4
+metric = proc.fd.count
+description = Open file descriptors
diff --git a/pcp/columns/guest b/pcp/columns/guest
new file mode 100644
index 00000000..89bb926b
--- /dev/null
+++ b/pcp/columns/guest
@@ -0,0 +1,17 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[guest]
+heading = GUEST
+caption = GUEST_TIME
+width = 6
+metric = proc.psinfo.guest_time
+description = Guest time for the process
+
+[cguest]
+heading = CGUEST
+caption = CGUEST_TIME
+width = 6
+metric = proc.psinfo.guest_time + proc.psinfo.cguest_time
+description = Cumulative guest time for the process and its children
diff --git a/pcp/columns/memory b/pcp/columns/memory
new file mode 100644
index 00000000..305a654a
--- /dev/null
+++ b/pcp/columns/memory
@@ -0,0 +1,39 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[vmdata]
+heading = VDATA
+width = 6
+metric = proc.memory.vmdata
+description = Virtual memory used for data
+
+[vmstack]
+heading = VSTACK
+width = -6
+metric = proc.memory.vmstack
+description = Virtual memory used for stack
+
+[vmexe]
+heading = VEXEC
+width = 6
+metric = proc.memory.vmexe
+description = Virtual memory used for non-library executable code
+
+[vmlib]
+heading = VLIBS
+width = 6
+metric = proc.memory.vmlib
+description = Virtual memory used for libraries
+
+[vmswap]
+heading = VSWAP
+width = 6
+metric = proc.memory.vmswap
+description = Virtual memory size currently swapped out
+
+[vmlock]
+heading = VLOCK
+width = 6
+metric = proc.memory.vmlock
+description = Locked virtual memory
diff --git a/pcp/columns/sched b/pcp/columns/sched
new file mode 100644
index 00000000..36b8b551
--- /dev/null
+++ b/pcp/columns/sched
@@ -0,0 +1,10 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[rundelay]
+heading = RUNQ
+caption = RUN_DELAY
+width = 4
+metric = proc.schedstat.run_delay
+description = Run queue time
diff --git a/pcp/columns/swap b/pcp/columns/swap
new file mode 100644
index 00000000..234b3db3
--- /dev/null
+++ b/pcp/columns/swap
@@ -0,0 +1,15 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[swap]
+heading = SWAP
+width = 5
+metric = proc.psinfo.nswap
+description = Count of swap operations for the process
+
+[cswap]
+heading = CSWAP
+width = 5
+metric = proc.psinfo.nswap + proc.psinfo.cnswap
+description = Cumulative swap operations for the process and its children
diff --git a/pcp/columns/tcp b/pcp/columns/tcp
new file mode 100644
index 00000000..f9a18196
--- /dev/null
+++ b/pcp/columns/tcp
@@ -0,0 +1,31 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[tcp_send_calls]
+heading = TCPS
+caption = TCP_SEND
+width = 6
+metric = bcc.proc.net.tcp.send.calls
+description = Count of TCP send calls
+
+[tcp_send_bytes]
+heading = TCPSB
+caption = TCP_SEND_BYTES
+width = 6
+metric = bcc.proc.net.tcp.send.bytes
+description = Cumulative bytes sent via TCP
+
+[tcp_recv_calls]
+heading = TCPR
+caption = TCP_RECV
+width = 6
+metric = bcc.proc.net.tcp.recv.calls
+description = Count of TCP recv calls
+
+[tcp_recv_bytes]
+heading = TCPRB
+caption = TCP_RECV_BYTES
+width = 6
+metric = bcc.proc.net.tcp.recv.bytes
+description = Cumulative bytes received via TCP
diff --git a/pcp/columns/udp b/pcp/columns/udp
new file mode 100644
index 00000000..060f0486
--- /dev/null
+++ b/pcp/columns/udp
@@ -0,0 +1,31 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[udp_send_calls]
+heading = UDPS
+caption = UDP_SEND
+width = 6
+metric = bcc.proc.net.udp.send.calls
+description = Count of UDP send calls
+
+[udp_send_bytes]
+heading = UDPSB
+caption = UDP_SEND_BYTES
+width = 6
+metric = bcc.proc.net.udp.send.bytes
+description = Cumulative bytes sent via UDP
+
+[udp_recv_calls]
+heading = UDPR
+caption = UDP_RECV
+width = 6
+metric = bcc.proc.net.udp.recv.calls
+description = Count of UDP recv calls
+
+[udp_recv_bytes]
+heading = UDPRB
+caption = UDP_RECV_BYTES
+width = 6
+metric = bcc.proc.net.udp.recv.bytes
+description = Cumulative bytes received via UDP
diff --git a/pcp/columns/wchan b/pcp/columns/wchan
new file mode 100644
index 00000000..893de587
--- /dev/null
+++ b/pcp/columns/wchan
@@ -0,0 +1,17 @@
+#
+# pcp-htop(1) configuration file - see pcp-htop(5)
+#
+
+[wchan]
+heading = WCHAN
+caption = WCHAN_ADDRESS
+width = 8
+metric = proc.psinfo.wchan
+description = Wait channel, kernel address process is blocked or sleeping on
+
+[wchans]
+heading = WCHANS
+caption = WCHAN_SYMBOL
+width = -12
+metric = proc.psinfo.wchan_s
+description = Wait channel, kernel symbol process is blocked or sleeping on